Through the delivery of specific wavelengths of light, particular effects can be accomplished, such as inactivation of bacteria, fungi, or viruses, facilitation of chemical reactions (e.g., curing of plastics or other materials), generation of heat, and conversion of light wavelength to an alternative wavelength.
White light is generally composed of multiple wavelengths of light from across the visible spectrum. White light is perceived, in part, by the sensitization of the S, M, and L cones (short, medium, and long, respectively) of the human eye. The S, M, and L cones react to wavelengths most commonly described as blue, green, and red, respectively. When a light source generates wavelengths in each of these cones at proper intensities, white light is perceived by the human eye. To perceive white light, all three cone types must be stimulated.
A conventional method to achieve the stimulation involves using a combination of light emitting diodes (LEDs) with different colors of emitted light. One challenge in manufacturing LED luminaires is that the LEDs frequently appear to have the wrong spectral output after manufacturing. When multiple LEDs are used in a luminaire, the combination of the differences can be amplified. When individual LEDs are manufactured, they sometimes go through certain quality control techniques, however, these quality control techniques usually only measure limited features of the LEDs, such as correlated color temperature (CCT) rating, which effectively measures how ‘warm’ (e.g., a red/orange appearance) or ‘cool’ (e.g., a blueish appearance) they appear. Through this process, the individual LEDs are separated by the CCT, which is referred to as binning. Different bins of LEDs, though, will often have slight differences from batch to batch, which can be discernible during use.